Molar Incisor Hypomineralisation

Question 1

What teeth does hypomineralisation affect

What is the prevalence of hypomineralisation?

Answer 1

Hypomineralisation of systemic origin of 1-4 permanent molars, frequently associated with affected incisors

10-20%

Question 2

What is hypomineralisation?

Answer 2

disturbance of enamel formation resulting in a reduced mineral content

(secretory phase set down but not mineralised/matured)

Question 3

What does true hypoplasia mean and what does aquired hypoplasia mean?

Answer 3

reduced bulk or thickness of enamel. May be:
* True - enamel never formed (scretory phase is affected but enamel mineralisation is normal)
* Aquired - post-eruptive loss of enamel bulk (parts of tooth have been lost due to hypomineralisation

Question 4

What did studies show in regards to pulpal innervation, immune cells and vascularisation of MIH patient?

Answer 4

increased neural density
increased immune cell accumulation
increased vascularity

Question 5

How does pain occur in MIH?

Answer 5

Dentine hypersensitivity: porous enamel or exposed dentine facilitates fluid flow within dentine tubules to activate A delta nerve fibres (hydrodynamic theory)

Peripheral sensitisation: underlying pulpal inflammation leads to sensitisation of C-fibres

Central sensitisation: From continued nociceptive activation.

Question 6

What is the critical period for formation of MIH and why?

Answer 6

• First year of life generally agreed
• Enamel matrix of crown of FPM’s is complete by one year

Question 7

What might be perinatal causes?

Answer 7

birth trauma/anoxia
pre term birth
hypocalcaemia

Question 8

What might be postnatal causes of MIH?

Answer 8

prolonged breast feeding
dioxins in breast milk
fever and medication
socioeconomic status

Question 9

What are the childhood diseases that may cause MIH?

Answer 9

measles
rubella
varicella

Question 10

What increases the odds of SDO (severe demarcated opacity)?

Answer 10

breastfeeding more than 6 months
late intro gruel >6 months
late intro infant formula >6 months

Question 11

What does yellow brown patches mean?

Answer 11

more porous - whole enamel layer

Question 12

What does white/cream mean?

Answer 12

inner parts of enamel affected

Question 13

What do chronologically dispersed hypomineralised demarcated opacities mean?

Answer 13

Higher carbon content, lower Ca, PO4

Question 14

What might children with MIH have in the future?

Answer 14

• 10x more treatment
• Fear and anxiety more common
• Behaviour management problems more common

Question 15

What are the treatment options for molars?

Answer 15

• Composite/GIC restorations
• Stainless steel crowns
• Adhesively retained copings
• Extraction (8.5 - 9.5 yrs)

Question 16

Why should lower FPM not be removed before 8?

Answer 16

8-9 years is usually the time when there is calcification of the bifurcation of the lower 7 - prevents 7 being misalighed by acting as placeholder

Question 17

What are the treatments possible for affected incisors?

Answer 17

• Acid pumice microabrasion
• Resin Inflitration
• External bleaching
• Localised composite placement
• Veneers